Roller ball assembly with superhard elements

ABSTRACT

A roller ball assembly is provided. The assembly includes a primary roller ball supported by a support element that is composed of a superhard material. The assembly includes a cup defining a cavity within which the support clement is positioned. A cap is coupled with the cup and positioned to retain the primary roller ball within the cavity. Also, a cup is disclosed for supporting roller halls. Additionally, disclosed are system and apparatus incorporating the assembly, as well as to methods of making and using the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.16/049,631, filed on Jul. 30, 2018 (allowed), the entirety of which isincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OF DEVELOPMENT

Not applicable.

FIELD

The present disclosure relates to roller ball assemblies, apparatus andsystems including the same, and methods of making, assembling, and usingthe same.

BACKGROUND

Roller ball assemblies, also known as transfer ball bearings, areemployed extensively in material handling and equipment applications.Such applications include but are not limited to: equal loaddistribution, aerospace & air cargo applications, die-handling, metalmanufacturing & fabrication, caster substitution, medical technologies &devices, industrial robotics, downhole drilling tools, downhole wirelineoperations, downhole coiled tubing operations, downhole completions,military logistics, measuring equipment, guides for small linear motion(e.g., photo copier slides), and transfer of material in clean rooms.

Roller ball assemblies typically include a primary ball supported by amultiplicity of smaller ball bearings in a containing cup. Typicalcomparative sizes are 1″, or 1¼″, or 1½″ diameter for the primary rollerball and ⅛″ diameter for the support balls. Over time, the primaryroller ball and especially the support balls are subject to pointloading, surface spalling, corrosion, and fatigue loading, leading tofailure of the roller ball assembly, Some precision applications employprimary balls as small as 4.8 mm and appropriately reduced diametersupport balls.

FIG. 1 depicts a cross-sectional view of atypical roller ball assembly100 of the prior art. In assembly 100, primary roller ball 101 issupported by a series of small steel balls 103 within shaped steel cup102. Primary steel roller ball 101 is retained by cap 105. Assembly 100also includes small weep holes 104 for clearing liquid or minor debris.

Some assemblies do not employ smaller ball bearings as support for theprimary roller ball, but rather use a direct engagement with a cupsurface. In order to overcome galling problems, these designs have, insonic instances, used coatings or lubricants, which require seals, oralternative roller ball materials, such as silicon nitride, tungstencarbide, silicon carbide, or ceramics. Even when coatings or alternativeroller ball materials are used, the increased surface contact area ofthe roller ball with the cup surface increases the coefficient offriction and reduces the free rolling capability of the roller ball.

An additional significant challenge is contamination with debris,hampering the free rolling of the primary roller ball. In the supportball of existing assemblies, debris evacuation openings in the lower cupstructure must be small enough to not catch or interfere with the freerolling of the secondary balls. This size limitation of the debrisevacuation openings limits their effectiveness in clearing contaminantsfrom the assembly.

Changing out failed or fouled roller ball assemblies is time consumingand disruptive to operations. This can be especially problematic inaerospace, downhole, and military logistics operations where limitedaccess exists or failure impacts mission critical performance.

Information on roller ball bearing assemblies can be found in the“Hudson Bearings Air Cargo Roller Ball Transfers”, an undated eight-pagebrochure, as well as in “Hudson Bearings Air Cargo Roller Ball TransfersInstallation and Maintenance Protocols”, an undated five-page brochure,both of which are available from the Hudson Bearings website(http://www.hudsonbearings.com). Of note from these brochures are the850 lbs. maximum load capacity rating and 400° F. maximum temperaturerange for heavy duty transfer roller ball assemblies.

An additional reference on the downhole use of roller ball assemblies isU.S. Pat. No. 9,803,432, to Wood et al., which is incorporated herein byreference in its entirety as if set out in full.

BRIEF SUMMARY

Some aspects of the present disclosure include a roller ball assembly.The assembly includes a primary roller ball that is supported by atleast one support element. Each support element is composed of asuperhard material.

Other aspects of the present disclosure include a cup for supporting aroller ball in a roller ball assembly. The cup includes a cup bodydefining a cavity. At least one support element is positioned in thecavity and coupled with the cup body. Each support element is composedof a superhard material.

Additional aspects of the present disclosure include a method ofsupporting a primary roller ball of a roller ball assembly. The methodincludes positioning at least one support element within a cavity of acup. Each support element is composed of a superhard material. Themethod includes positioning the primary roller ball within the cavitysuch that an outer surface of the primary roller ball is in contact withan engagement surface of the at least one support element. The methodincludes positioning a cap relative to the cup such that the cap ispositioned to retain the primary roller ball within the cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features and advantages of the systems,apparatus, and/or methods of the present disclosure may be understood inmore detail, a more particular description briefly summarized above maybe had by reference to the embodiments thereof which are illustrated inthe appended drawings that form a part of this specification. It is tobe noted, however, that the drawings illustrate only various exemplaryembodiments and are therefore not to be considered limiting of thedisclosed concepts as it may include other effective embodiments aswell.

FIG. 1 is a cross-sectional view of a typical roller ball assembly ofthe prior art.

FIG. 2 is a flow chart of a method in accordance with certain aspects ofthe present disclosure.

FIG. 3 is a side view of an embodiment of a roller ball assembly of thepresent application.

FIG. 4 is a top view of a cup of a three-support element assembly of thepresent technology without roller ball or cap.

FIG. 5 is a side view of an alternative embodiment of the technology ofthis application.

FIG. 6 is a side view of an alternative embodiment of the technology ofthis application.

FIG. 7A is a top view of an alternative embodiment of the technology ofthis application without roller ball or cap.

FIG. 7B is a side view of the assembly of FIG. 7A with cap and rollerball included.

FIG. 8 is a diagram showing the location spectrum from centerline for asingle support at centerline, or for multiple supports angled upwards onthe cup from centerline.

Systems, apparatus, and methods according to present disclosure will nowbe described more fay with reference to the accompanying drawings, whichillustrate various exemplary embodiments. Concepts according to thepresent disclosure may, however, be embodied in many different forms andshould not be construed as being limited by the illustrated embodimentsset forth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough as well as complete and will fully conveythe scope of the various concepts to those skilled in the art and thebest and preferred modes of practice.

DETAILED DESCRIPTION

Certain aspects of the present disclosure include roller ballassemblies, apparatus including roller ball assemblies, systemsincluding roller ball assemblies, methods of making roller ballassemblies, methods of assembling roller ball assemblies, and methods ofusing roller ball assemblies.

Roller Ball Assemblies Including Superhard Materials

In some embodiments, the technology of this application provides for ahigh-performance roller ball assembly with a moving part (optionally asingle moving part), in particular a primary roller ball, supported onat least one so called “superhard” component or element (i.e., acomponent composed of a “superhard material”). As would be understood byone skilled in the art, “superhard materials” are a category ofmaterials defined by the hardness of the material, which may bedetermined in accordance with the Brinell, Rockwell, Knoop and/orVickers scales. For example, superhard materials include materials witha hardness value exceeding 40 gigapascals (GPa) when measured by theVickers hardness test. As used herein, superhard materials includematerials that are at least as hard as tungsten carbide tiles and/orcemented tungsten carbide, such as is determined in accordance with oneof these hardness scales, such as the Brinell scale. One skilled in theart would understand that a Brinell scale test may be performed, forexample, in accordance with ASTM E10-14, the Vickers hardness test maybe performed, for example, in accordance with ASTM E384; the Rockwellhardness test may be performed, for example, in accordance with ASTME18; and the Knoop hardness test may be performed, for example, inaccordance with ASTM E384. The “superhard materials” disclosed hereininclude, but are not limited to, tungsten carbide (e.g., tile orcemented), infiltrated tungsten carbide matrix, silicon carbide, siliconnitride, cubic boron nitride, and polycrystalline diamond.

Thus, some aspects of the present disclosure include employing discretesuperhard elements to support a roller ball. In certain aspects of thetechnology of this application, the need for small diameter supportballs in a roller ball assembly is eliminated. Thus, at least some ofthe roller ball assemblies disclosed herein lack (i.e., do not include)small diameter support balls.

In certain embodiments, the roller ball assemblies disclosed herein havea higher load bearing capacity, higher temperature capacity, are moredurable, are more corrosion resistant, are smoother running, and have agreater capacity for the passing of contaminants and larger debris fromthe working area of the assembly in comparison to existing roller ballassemblies.

In some aspects, the roller ball assemblies disclosed herein“self-clean” any corrosion on the primary roller ball. As the surface ofthe primary roller ball moves, while engaged with the surface of thepolycrystalline diamond elements, existing corrosion on the primaryroller ball may be at least partially removed therefrom via thefrictional threes resulting from the engagement between the surfaces ofthe primary roller ball and the polycrystalline diamond elements. Thatis, the polycrystalline diamond elements clean, sweep, or rub off atleast some of the corroded material of the primary roller ball. Incontrast, roller ball assemblies such as is shown in FIG. 1 includeprimary roller balls that “roll” on other, small roller balls, which donot function to remove corroded material from the primary roller ball.

In certain embodiments, the technology of this application includes aroller ball assembly suitable for application in harsh environments(e.g., downhole environments). The technology of this applicationincludes a roller ball assembly capable of application in downholedrilling applications in the mitigation of torque and drag.

Exemplary Testing

Applicants of the present application have conducted significant testingon an exemplary roller ball assembly that provides anultra-high-performance alternative in comparison to existing technology.Table 1, below, sets forth a summary of a test performed by theApplicants of an exemplary configuration of a roller ball assembly ofthe present disclosure.

TABLE 1 Tested Mechanism - Bearing Steel Ball in Alloy Steel Cup AgainstRotating Surface Steel Cam Surface RPM Speed Loading Result Test TripodPolished 200 1.13 m/s 700 lbf 20 hr. test, PDC 1.50″ Ball little wear onBall; slight Hertzian trace on PDCs

FIG. 2 sets forth the steps of the testing performed, which included:supporting a single 1½″ high-carbon steel roller ball on threepolycrystalline diamond (PDC) elements, box 290; deploying the supportedroller ball in a steel cup, box 291; subjecting the deployed roller ballto 20 hours of rotating test under 700 lbf of load, box 292; andassessing wear roller ball and PDC elements, box 293. As is evident fromTable 1, the testing resulted in little wear on the roller ball and onlya slight Hertzian trace of discoloration on the PDC elements.

In further testing, 800 lbs of load on the primary roller ball of aprior art roller ball assembly was found to produce 525,000 PSI maxstress on the associated support ball. Whereas, in an exemplary rollerball assembly in accordance with the present disclosure, 1,600 lbs ofload on the primary roller ball was required to produce the same 525,000PSI max stress on the associated superhard element. Consequently,without being bound by theory, the technology disclosed herein exhibitedtwice the load bearing capacity in comparison to the prior art rollerball assembly.

Turning now to FIGS. 3-8, various exemplary roller ball assemblies andaspects thereof will now be described. In FIGS. 3-8, like referencenumerals refer to like elements. For example, an exemplary cup isidentified with reference numeral “302” in FIG. 3 and is identified withreference numeral “402” in FIG. 4.

Ball Assembly with Superhard Support Elements

FIG. 3 is a side view of a roller ball assembly 300 in accordance withan embodiment of the present application. In assembly 300, roller ball301 is supported within cup 302 (cup body) via support elements 303.Each support element 303 is formed of a superhard material. Roller ball301 may be formed of any of a variety of materials including, but notlimited to, steel. As shown in FIG. 3, roller ball 301 is supported bysupport elements 303 via contact between roller ball outer surface 320(also referred to as engagement surface) and support element surfaces322 (also referred to as opposing engagement surfaces). Primary rollerball 301 is clear of (i.e., not in contact with) cup 302. Supportelements 303 are attached to, embedded within, or otherwise affixed toand/or coupled with or within cup 302. In contrast to small supportroller halls, such as is shown in FIG. 1, support elements 303 arestatic relative to cup 302. In operation, primary roller ball 301 movesin sliding contact with support elements 303,

Cup 302, also referred to as “shaped cup”, has a shape that defines acavity 350 configured to receive roller ball 301 therein, and to allowrolling of roller ball 301 therein. Cup 302 may be formed on any of avariety of materials including, but not limited to steel.

Assembly 300 includes cap 305. Cap 305 is positioned relative to cup 302to retain primary roller ball 301 within cup 302. Cap 305 is engagedand/or coupled (e.g., affixed) with cup 302 at top end 332 of cup 302.Cap 305 has a curvature 340 sufficient to retain roller ball 301 withincup 302 such that, in operation, roller ball 301 is supported viasupport elements 303 and freely rolls within cup 302 while beingretained therein by cap 305. Cap 305 is clear of (i.e., not in contactwith) primary roller ball 301. Cap 305 may be formed on any of a varietyof materials including, but not limited to, steel. Cap 305 may be, forexample, in the form of a retainer ring.

Assembly 300 includes debris clearance hole 304 positioned at the bottomend 330 of cup 302. Hole 304 may be sized and arranged for clearance oflarge debris from cup 302. Contrary to the hole 204 of FIG. 1, hole 304is not limited in size by the presence of small supporting roller ballsthat would fall through the hole if the hole were too large. Thus, whilehole 304 may be as small or smaller than hole 204, hole 304 may also belarger, even significantly larger, than hole 204. For example, hole 304may be up to about half the size of primary roller ball 301 (e.g., halfthe diameter), or from about 118 to about ½ the size (e.g., diameter) ofprimary roller ball 301, or from about ¼ to about ½ the size (e.g.,diameter) of primary roller ball 301.

One skilled in the art would understand that the roller ball assemblydisclosed herein is not limited to the particular arrangement shown inFIG. 3 (or FIGS. 4-8). For example, the roller ball assembly may includemore or less than three support elements, which may be arranged, sized,and positioned in numerous configurations.

Cup Assembly

FIG. 4 is a top view of a cup that includes a three-support elementassembly (i.e., three support elements, 403) in accordance with certainaspects of the present technology. Cup 402 is shown in FIG. 4 without aroller ball engaged therein and without a cap engaged thereon.

Support elements 403, formed of a superhard material, are deployed andpositioned within cup 402. Support elements 403 may be coupled to, with,or within cavil surface 452 of cup 402 via any of a variety of methods,as is known in the art. Debris clearance hole 404 is positioned at thebottom end of cup 402, as a through-hole through cavity surface 452.

While shown as evenly spaced in FIG. 4, one skilled in the art wouldunderstand that support elements 403 may be spaced unevenly.

Roller Ball Assembly with Superhard Support and Retention Elements

FIG. 5 shows a side view of roller hail assembly 500, exemplifying analternative embodiment of the technology of this application. Inassembly 500, roller ball 501 is supported by support elements 503(formed of superhard material) that are positioned within cup 502 and isfurther retained by retention elements 506 (formed of superhardmaterial) deployed, positioned, and arranged on or within cap 505 suchthat opposing engagement surfaces 522 of both support elements 503 andretention element 506 are engaged with outer surface 520 of roller ball501.

Retention elements 506 may be coupled to, with, or within cap 505 in thesame manners as described with respect to the coupling of supportelements with the cup. In certain aspects, retention elements 506 are ofthe same or substantially structure the same as support elements 503. Asis evident in FIG. 5, support elements 503 are positioned below ahypothetical axis of rotation 560 of roller ball 501 to support downwardforce 570 of roller ball 501, and retention elements 506 are positionedabove the hypothetical axis of rotation 560 of roller ball 501 tosupport upward force 572 of roller ball 501.

As with other embodiments, assembly 500 includes debris clearance hole504 positioned at the bottom end 530 of cup 502.

FIG. 6 depicts a side view of roller ball assembly 600 in accordancewith an alternative embodiment of the technology of this application. Inassembly 600, roller ball 601 is supported by support elements 603 andadditional support elements 607, each formed of superhard material andpositioned within cup 602; and is retained by retention elements 606,which is formed of superhard material and is deployed and positioned incap 605. Debris clearance hole 604 is deployed at the bottom end 630 ofcup 602. Each of support elements 603, additional support elements 607,and retention elements 606 has an engagement surface 622 in slidingcontact with outer surface 620 of roller ball 601.

Cup Assembly with Cut Out Relief and Lubricating Element

FIG. 7A is a top view of cup 702 including a three-support elementassembly (i.e., three support elements, 703) in accordance with certainaspects of the present technology. Cup 702 is shown without a rollerball engaged therein and without a cap engaged thereon.

Support elements 703, formed of superhard material, are deployed andpositioned in cup 702. Debris clearance hole 704 is formed through thebottom of cup 702, through cavity surface 752.

Cup 702 includes cut out relief areas 708 formed there-through (e.g.,through the frame, body, structure). Support elements 703 are positionedbetween cut out relief areas 708. Cut out relief areas 708 may be holesformed through cavity surface 752 and may allow debris to passthere-through.

Cup 702 also includes lubricating element 709 positioned to provide alubricant within cup 702, between cup 702 and any roller ball that ispositioned therein, such as between engagement surfaces of supportelements 703 and the outer surface of a roller ball.

FIG. 7B shows a side view of roller ball assembly 700, which includescup 702 with support elements 703, debris clearance hole 704, cut outrelief areas 708, and lubricating element 709 as shown in FIG. 7A, withthe addition of primary roller hall 701 and cap 705 (retaining cap).

In assembly 700, roller ball 701 is supported within cup 702 via supportelements 703, which are formed of superhard material, and is retainedwithin cup 702 via cap 705. In operation, as roller ball 701 rolls insliding contact with engagement surface 722 within cup 702, relief areas708 and hole 704 allow for debris fall out there-through.

Lubricating element 709 is engaged with (e.g., pressed against) outersurface 720 of primary roller hall 701. Energizer 710, which may be abias member, such as a spring, presses lubricating element 709 intoengagement with outer surface 720 of roller ball 701. Thus, lubricatingelement 709 is positioned to apply lubricant to outer surface 720 ofroller ball 701. In some aspects, the lubricant is any one of a numberof solid lubricants including but not limited to: graphite, hexagonalboron nitride, oil releasing polymer, molybdenum disulfide, or tungstendisulfide. In some aspects, energizer 710 is a coil spring, a Bellevillespring, an elastomer, or other applicable energizing element.

Although FIGS. 7A and 7B show cap 705 without superhard retentionelements, it would be clear to one skilled in the art that a capcontaining superhard retention elements, such as shown in FIGS. 5 and 6,could be used in the assembly of FIGS. 7A and 7B.

Positioning of Superhard Supporting Elements

FIG. 8 is a representative diagram of an arc 811 identifying positionswhere supporting elements of superhard material may be deployed within acup in accordance with certain aspects of the technology of the presentapplication. Arc 811 is bisected by vertical centerline 814. Arc 811corresponds with the bottom, cavity surface of a cup of a roller ballassembly, as indicated via 852. Thus, centerline 814 corresponds withthe centerline of a cup of a roller ball assembly or with the centerlineof the roller ball of a roller ball assembly.

In embodiments where a single support element formed of superhardmaterial is deployed, support element 812 is deployed as the supportelement at the base of arc 811 with the face 822 a (engagement surfaceformed of superhard material) arranged and positioned perpendicular tocenterline 814.

In embodiments where more than one support element formed of superhardmaterial are deployed, support elements 813 (formed of superhardmaterial) are deployed at positions that are generally equidistant fromcenterline 814 and at an arc angle from centerline 814 along arc 811. Agenerally minimum angle for deployment of multiple superhard supportelements is shown at C. The value for angle C is about 20° fromcenterline 814. A more preferred spectrum of angles for deployment ofsuperhard support elements is shown by angles D and E, which are fromabout 30° at D to about 50° at E, both from centerline 814. A generallymaximum angle for deployment of multiple superhard support elements isshown at F. The value for angle F is about 60° from centerline 814. Itwould be understood by those skilled in the art that the angles shown inFIG. 8 apply to the primary superhard support elements and do not applyto additional superhard retention elements that may be deployed in aretaining cap or ring of a roller ball assembly.

Roller Ball

In the practice of the technology of this application, the primaryroller ball is preferably stainless steel or hard carbon steel, but may,alternatively, be tungsten carbide, silicon carbide, silicon nitride,alternative ceramics, nylon or any other bearing ball material as knownin the art.

Support of the Roller Ball

Although superhard components are typically more expensive (financially)than existing small diameter support roller balls, the technology of thepresent application offers clear advantages over existing primary rollerball supports. The roller ball assembly technology of the presentapplication includes, in some instances, only a single moving part,i.e., the primary roller ball, with no other moving parts in the rollerball assembly. The engagement of the primary roller ball with thesuperhard components (support and retention elements), especiallypolished PDC elements, provides for very low-friction rolling of theprimary roller ball. In some aspects, the coefficient of friction (CoF)of the engagement between the primary roller ball and the PDC elementsremains constant or substantially constant over relatively long terms ofuse, as the assembly does not rely on use of small roller balls (e.g.,as shown in FIG. 1), which are subject to degradation that affects theCoF. The superhard components are also capable of higher loading thanexisting small diameter support roller balls.

Retaining Cap

In the embodiments disclosed herein, the retaining caps or rings (e.g.,cap 205) may be held in place on the respective cup of the roller ballassembly via methods known in the art including, but not limited to, oneor more snap rings, gluing, threading, welding, brazing, or pressfitting the cap or ring to the cup. In some aspects, the retaining capis designed to incorporate a debris excluding “knife edge”, as is knownin the art, or a sealing surface. Alternatively, the retaining cap orring may be slotted, scalloped or gapped to allow for the free flow offluid, such as in a downhole application of the roller ball assembly.

Mounting of Support and Retention Elements

The superhard support and retention elements deployed in the variousembodiments of the technology of this application may be mounted (e.g.,onto the cup and/or cap) via one or more methods, as known in the art,including but not limited to brazing, gluing, threading, or pressfitting the superhard support and retention elements to the cap or cup.

Superhard Materials

Although the technology of this application is broad enough to includethe use of a range of superhard materials, in some applications thepreferred superhard material is PDC. While polished PDC is preferred inthe technology of the present application, the PDC employed in thistechnology may be lapped, highly lapped, polished, or highly polished.U.S, Pat. Nos. 5,447,208 and 5,653,300, to Lund et al., providedisclosure related to PDC and the surface finish thereof. Thedisclosures of U.S. Pat. Nos. 5,447,208 and 5,653,300 are incorporatedherein by reference and made a part of the present disclosure. As usedherein, a surface is defined as “highly lapped” if the surface has asurface finish of 20 μin or about 20 μin, such as a surface finishranging from about 18 to about 22 μin. As used herein, a surface isdefined as “polished” if the surface has a surface finish of less thanabout 10 μin, or of from about 2 to about 10 μin. As used herein, asurface is defined as “highly polished” if the surface has a surfacefinish of less than about 2 μin, or from about 0.5 μin to less thanabout 2 μin. In some aspects, engagement surface has a surface finishranging from 0.5 μin to 40 μin, or from 2 μin to 30 μin, or from 5 μinto 20 μin, or from 8 μin to 15 μin, or any range therebetween. In someaspects, engagement surface has a surface finish of less than 40 μin,less than 30 μin, less than 20 μin, less than 15 μin, less than 10 μin,less than 8 μin, less than 5 μin, or less than 2 μin. Polycrystallinediamond that has been polished to a surface finish of 0.5 μin has acoefficient of friction that is about half of standard lappedpolycrystalline diamond with a surface finish of 20-40 μin.

Thus, in some aspects, the technology disclosed herein incorporates theuse of superhard elements, preferably polished polycrystalline diamondcompact (PDC) elements, to support the primary roller ball of a rollerball assembly.

Arrangement and Configuration of Superhard Support and/or RetentionElements

In one preferred embodiment, three planar superhard support elements arecomplimentarily deployed in a metal cup or frame. In operation, thesuperhard support elements provide the primary support for the rollerball. Several alternatives are possible for the supporting elements ofthe technology of this application including an increased or decreasednumber of superhard support elements. For example, a single superhardsupport element may be deployed in the bottom of the metal cup tosupport the roller ball.

Although planar superhard support elements are preferred, non-planar,including concave or convex, superhard support elements may be used.

The upper girth of the roller ball may be contained (retained) by anumber of materials or combinations of materials as known in the artincluding, but not limited to, polypropylene, Kevlar, metal, felt,leather, or Teflon. However, in an enhanced embodiment, the upperportion of the roller ball is contained (retained) by an additional setof superhard, preferably polished PDC elements (i.e., retentionelements), secured on an inner surface or bosses of a cap of metal orother appropriate material.

The superhard components (support or retention elements) of the presenttechnology may generally be as small as ⅛″ (about 3 mm) in diameter oras large as ¾″ (about 19 mm) in diameter. For smaller precisionapplications, significantly smaller diameter support and retentionelements and smaller primary ball diameters may be used. As would beunderstood by one skilled in the art, the technology of the presentapplication may be scaled up or down without departing from the primarytechnology. When two or more superhard components are used to supportthe transfer roller ball, the superhard components are typically,although not necessarily, located equidistant from the assemblycenterline (as shown and described with reference to FIG. 8).

As would be understood by one skilled in the art, the various aspectsdisclosed herein may be combined in any of numerous combinations withoutdeparting from the scope of this disclosure. For example, a roller ballassembly that includes a primary roller ball supported on at least onesupport clement that is formed of a superhard material may furtherinclude: at least one retention element formed of a superhard material;at least one additional support element formed of a superhard material;at least one large debris clearance hole; at least one lubricatingelement; or any combination thereof.

From the descriptions and figures provided above it can readily beunderstood that the technology of the present application may beemployed in a broad spectrum of applications, including those indownhole environments. The technology provided herein additionally hasbroad application to other industrial applications.

Furthermore, while shown and described in relation to engagement betweenthe surface of a roller ball and the surface of a support element thatincludes superhard material, one skilled in the art would understandthat the present disclosure is not limited to this particularapplication and that the concepts disclosed herein may be applied to theengagement between any surface (e.g., steel surface) that is engagedwith the surface of a superhard material.

Although the present embodiments and advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the disclosure. Moreover, the scope of the present applicationis not intended to be limited to the particular embodiments of theprocess, machine, manufacture, composition of matter, means, methods andsteps described in the specification. As one of ordinary skill in theart will readily appreciate from the disclosure, processes, machines,manufacture, compositions of matter, means, methods, or steps, presentlyexisting or later to be developed that perform substantially the samefunction or achieve substantially the same result as the correspondingembodiments described herein may be utilized according to the presentdisclosure. Accordingly, the appended claims are intended to includewithin their scope such processes, machines, manufacture, compositionsof matter, means, methods, or steps.

1. A roller ball assembly comprising: a primary roller ball supported byat least one support element, wherein the at least one support elementis composed of a superhard material.
 2. The roller ball assembly ofclaim 1, wherein the superhard material is at least as hard as tungstencarbide.
 3. The roller ball assembly of claim 1, wherein the superhardmaterial comprises tungsten carbide, silicon carbide, or cubic boronnitride.
 4. The roller ball assembly of claim 1, wherein the superhardmaterial comprises polycrystalline diamond.
 5. The roller ball assemblyof claim 4, wherein the polycrystalline diamond, at an engagementsurface of the at least one support element, is highly lapped, polished,or highly polished.
 6. The roller ball assembly of claim 5, wherein thepolycrystalline diamond, at an engagement surface of the at least onesupport element, has a surface finish that is equal to or less than 20μin.
 7. The roller ball assembly of claim 1, further comprising a cup,wherein the at least one support element is positioned in and coupledwith the cup, and wherein the primary roller ball is supported withinthe cup by the at least one support element.
 8. The roller ball assemblyof claim 7, wherein an outer surface of the primary roller ball isengaged with an engagement surface of the at least one support element,and wherein the primary roller ball is clear of the cup.
 9. The rollerball assembly of claim 7, further comprising a cap coupled with the cup,wherein the cap is positioned to retain the primary roller ball withinthe cup.
 10. The roller ball assembly of claim 9, further comprising atleast one retention element coupled with the cap, wherein the at leastone retention element has an engagement surface that is engaged with anouter surface of the primary roller ball such that the primary rollerball is supported within the cup by the at least one support element andis retained within the cup by the at least one retention element, andwherein the at least one retention element is composed of a superhardmaterial.
 11. The roller ball assembly of claim 7, further comprisingcut out relief areas formed through the bottom end of the cup.
 12. Theroller ball assembly of claim 11, wherein the cut-out relief areas arepositioned between support elements, and wherein the support elementsare positioned at the bottom end of the cup.
 13. The roller ballassembly of claim 7, further comprising a lubricating element positionedrelative to the cup to provide a lubricant between the cup and theprimary roller ball.
 14. The roller ball assembly of claim 13, furthercomprising an energizer positioned to force the lubricating element toengage with an outer surface of the primary roller ball to apply thelubricant to the outer surface of the primary roller ball.
 15. Theroller ball assembly of claim 7, wherein the roller ball assemblyincludes a single support element.
 16. The roller ball assembly of claim15, wherein the single support element is positioned at a base of thecup and is centered along a centerline of the primary roller ball. 17.The roller ball assembly of claim 7, wherein the roller ball assemblyincludes multiple support elements.
 18. The roller ball assembly ofclaim 17, wherein each support element is positioned along a base of thecup at positions that are equidistant from a centerline of the primaryroller ball and at arc angles from the centerline of the primary rollerball.
 19. The roller ball assembly of claim 18, wherein the supportelements are positioned at arc angles of at least 20° and at most 60°from the centerline.
 20. The roller ball assembly of claim 7, furthercomprising a debris clearance hole positioned at a bottom end of the cup21. (canceled)
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